For the sixth straight year, Marin led Bay Area counties in the number of complaints filed during winter "Spare the Air" days when burning in fireplaces is prohibited, air quality officials reported Tuesday.

The Bay Area Air Quality Management District received 1,058 complaints from Marin residents about smoke during "Spare the Air" alerts — about one-fifth of the Bay Area total. Marin has led the category every year since the inception of the program.

"There are lot of inland valleys in Marin and smoke tends to accumulate in those areas," said Ralph Borrmann, air district spokesman. "There are also active groups in areas like West Marin who call in."

The district also is aware of difficulties facing areas, such as Woodacre, where access to natural gas is limited and many people rely on wood for heat. The rules include exemptions for those families and businesses who burn wood to stay warm, yet people may still call to report smoke from those buildings.

This is the sixth year the district has cracked down on people who burn wood on days when weather conditions make it likely smoke will hang in the air and cause particulate pollution, making it difficult for some people to breathe.

"People get frustrated they can't burn and we end up selling a lot of gas stoves," said Barry Hovis, an employee at Blaze Fireplaces in San Rafael.

He estimates gas stoves make up at least 80 percent of business, but that there still is a demand for wood stoves.

"Lots of people like wood," Hovis said. "That's what they grew up with."

A lack of rainfall in Marin and the Bay Area through early February, along with light winds and cool temperatures combined to create a high number of no-burn days this season, air officials noted. The district called 30 "Spare the Air" days during the Nov. 1 through Feb. 28 period, tying a record established in 2006-07 season.

"This dry winter brought with it an unprecedented stretch of bad air quality and no-burn days," said Jack Broadbent, the air district's executive officer, in a statement.

Marin County had the third-highest number of confirmed violations, 40, behind San Mateo and Sonoma counties, according to district data.

Those who were caught violating the air rule this past season were assessed a $100 penalty. Each violation had to be confirmed by an inspector from the air district. A second-time burn offender faced a $500 fine.

Those who were cited can get out of paying by going to "smoke school." That requires enrolling in an online course that takes about 30 minutes to complete.

Air district officials say that on bad-air nights during the winter, smoke from 1.4 million fireplaces and wood stoves in the Bay Area accounts for 33 percent of the particulate matter that pollutes the air, outpacing cars, which account for 23 percent of the pollution. Particulate matter measures about one-seventh the diameter of a human hair and can pass through the nose and throat and lodge deep in the lungs, causing potential health issues.

• The Surgeon General has determined that there is no safe level of exposure to ambient smoke!

• If you smell even a subtle odor of smoke, you are being exposed to poisonous and carcinogenic chemical compounds!

• Even a brief exposure to smoke raises blood pressure, (no matter what your state of health) and can cause blood clotting, stroke, or heart attack in vulnerable people. Even children experience elevated blood pressure when exposed to smoke!

• Since smoke drastically weakens the lungs' immune system, avoiding smoke is one of the best ways to prevent colds, flu, bronchitis, or risk of an even more serious respiratory illness, such as pneumonia or tuberculosis! Does your child have the flu? Chances are they have been exposed to ambient smoke!